st: tuples, stepwise and counting types of variables

Dear Statlist i would be greatful if someone could help with the
following problem:
I have a number of "groups" of variables as examplified below.
local gr1 x1 x2 x3 x4
local gr2 x5 x6 x7 x8
local gr3 x9 x10 x11 x12 x13 x14 x15
local gr4 x16 x17
I run stepwise regressions for all the combinations of these groups
using tuples.
tuples "`gr1'" "`gr2'" "`gr3'" "`gr4'" , display
forval i = 1/`ntuples' {
qui stepwise, pr(0.05): regress y `tuple`i''
}
Now i would like to count how many variables from each group that
stayed in the step wise model.
For instance in the stepwise regression of gr1 and gr2 (ei x1 x2 x3
x4 x5 x6 x7 x8) only x3 x4 x5 was included in the regression. I
would then like an output along the lines of:
Model Num_var_gr1 num_var_gr2 num_var_gr3 num_var_gr4
gr2 gr3 1 2 0
0
gr2 gr4
gr1 gr2
any advise greatly appriciated, thanks
Thomas Sohnesen
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